Legendary investor Warren Buffett has sold down his shareholding in ailing Tesco by almost 30%.

Results from his Berkshire Hathaway investment company showed Buffett sold about 115m shares in the retail giant last year, 35m more than previously reported, leaving him with just over 300m, or about 3.7% of the company.

Tesco remains his 13th largest single shareholding, behind the likes of Coca-Cola, American Express and IBM, but at present it is the only one of Berkshire's 15 biggest shareholdings to be worth less than he paid for it, and is now valued at just over £990m.

In a letter to Berkshire shareholders, Buffett did not mention Tesco but affirmed his faith in long-term investments, advising his readers to "invest in stocks as you would in a farm".

The sale may be a further knock to wider faith in Tesco's prospects. Last week Philip Clarke, the firm's chief executive, dropped a pledge to target a profit margin of 5.2% and indicated fewer stores would open this year.